Many industrial applications require a dependable delivery of large quantities of sand or other granulated or powdered materials in carefully measured amounts. One of the most demanding applications is the preparation of fracturing fluid commonly used in oil well applications. Sand is the principal ingredient of fracturing fluid and oil well applications require a high volume of fracturing fluids to be continuously pumped into the bore hole at high pressure. Thus, vast, but metered, quantities of sand must be continually delivered to mixing facilities during fracturing applications. Further, the use of fracturing fluid demands careful control of tolerances in density and other parameters that are a function of the sand content.
Fracturing fluid applications use carefully graded sand of substantially uniform and repeatable characteristics. However, the sand component of fracturing fluid is very abrasive, even unto itself. Excess handling of the sand tends to reduce it into finer particles, thereby producing a sand of uncertain and uncontrolled characteristics which results in an inferior quality fracturing fluid.
It is the object of the present invention to provide a delivering and metering device that will carefully control the passage of a measured bulk quantity of granulated or powdered material; is capable of prolonged and continuous operation for high volumes of granulated or powdered material; and minimizes the handling of that material.
The present invention is illustrated throughout the specification as a device for delivering and metering sand for making fracturing fluid. However, this application is illustrative only and other applications will be fully taught and clearly apparent from this disclosure to persons having ordinary skill in the art.